Please, even without conspiracy theories like this, Equestria has always been a dark place.

They have Giant Bears the size of mountains made of stars roaming around. Greedy Dragons that could annihilate Equestria should they choose to attack it rather than simply flying over. Magic literally powered by hate. The pony species nearly finding itself extinct due to a combination of starvation and magical freezing thanks to, what was most likely, generations of tribal feuding and hatred. Then we have open slavery practiced by Sombra, and the Diamond Dogs don't see too against it either. Shapeshifters that feed off of love till your little but a withered husk. A mad god who will break your mind for lulz. Then the very first villain of the show attempted global genocide by blocking the sun. So yeah, Equestria is not all sunshine and rainbows like we first thought back in season one. We don't even need conspiracy theories to prove that.